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There are two prominently used virtualization architectures: Hosted architecture and Bare-metal architecture. The two architectures differ in the amount of control the VMM has on the underlying hardware and the host machine, which in turn has an impact on the performance of the applications running on the virtual machines. The Hosted architecture is suitable for virtualizing PC platforms which cannot be virtualized using the traditional mainframe approach of the Bare-metal architecture.
Key Terms in this Chapter
Bare Metal Architecture: The virtualization architecture in which the guest operating system runs on the top of the hypervisor that in turn runs directly on the host hardware and mediates the access requests for the host resources.
Virtualization: The technology that allows running more than one operating system side-by-side just on the same processing hardware.
Hypervisor: Facilitates the communication of the guest operating system and its applications with the host operating system and access the host resources without violating the privileges. A hypervisor is also referred to as the Virtual Machine Monitor (VMM).
Binary Translation: The virtualization technique in which the machine language code of an application for the guest operating system is translated to the machine language code of the host operating system (according to the latter's Instruction Set Architecture).
Hosted Architecture: The virtualization architecture in which the guest operating system runs on the top of the hypervisor and host operating system and access the host resources through the latter.
Shadow Page Table: The shadow page table is a data structure that is actively maintained and re-filled by the VMM. The shadow page table mirrors what the guest is doing in terms of its own page tables and in terms of what the VMM translates the guest physical address to the host physical address.
Virtual Machine: An instance of a guest operating system running on a host machine.
Cloud Computing: A utility-based computing where applications, platforms, storage and etc are provided as a service to the users over the Internet.